1. Field of the Invention
The present invention relates to an electron emission device, and, more particularly, to an electron emission device in which a size of a beam-passing opening is set within a range in response to a vertical pitch of a pixel to minimize (or reduce or prevent) electron beams from striking and exciting unwanted pixels in a vertical direction, thereby improving the uniformity of the resolution.
2. Description of Related Art
An electron emission device (e.g., a field emitter array (FEA) device, a ballistic electron surface (BSE) device, a surface conduction emission (SCE) device, a metal-insulator-metal (MIM) type device, and a metal-insulator-semiconductor (MIS) device, etc.) includes first and second substrates facing each other. Electron emission regions are formed on the first substrate. Cathode and gate electrodes functioning as driving electrodes for controlling the emission of electrons from the electron emission regions are also formed on the first substrate. Formed on a surface of the second substrate facing the first substrate are a phosphor screen and an anode electrode for placing the phosphor screen in a high potential state.
The first and the second substrates are sealed together at their peripheries using a sealing material such as frit, and the inner space between the substrates is exhausted to form a vacuum chamber (or a vacuum vessel). Arranged in the vacuum vessel are a plurality of spacers for uniformly maintaining a gap between the first and second substrates.
The typical electron emission device further includes a focusing electrode for focusing the electron beams from the electron emission regions. The focusing electrode is spaced apart from the gate electrode with a gap (which may be predetermined) therebetween. That is, the focusing electrode is spaced apart from the gate electrode.
The focusing electrode is provided with a plurality of beam-passing openings corresponding to pixels of the phosphor screen. That is, the size of each beam-passing opening may be designed to be identical to each corresponding pixel.
However, when the electron beam reaches a target pixel via the beam-passing opening, a size of the electron beam reaching the target pixel may be greater than that of the target pixel. In this case, the beam may strike the target pixel and an unwanted pixel adjacent to the target pixel, thereby exciting the unwanted pixel.
Therefore, a degree of luminescence from the target pixel is lowered, and thus the overall resolution of the phosphor screen is deteriorated.